With hot-cross buns, “go easy on toppings and try using low-fat spread instead of butter”, says the British Nutrition Foundation, adding that “lamb can be high in saturated fat” and any roast dinner should “include lots of fresh vegetables to help reach your five a day”.

This kind of sanctimonious advice is entirely in keeping with the approach of the public health lobby, which is the modern equivalent of the old temperance movement of late Victorian times.

So the quango Public Health England is spending £11million this year on its Change 4 Life publicity campaign, which aims to transform the nation’s habits.

“Have a smaller bottle of beer instead of a can,” goes one typically patronising tip.

What the puritans ignore is human nature

Health fanatics like to pretend that all their admonitions are based on uncontested science but this is just wishful thinking.

Contrary to their claims there is no agreement among experts about what constitutes a healthy diet.

In fact, some of their advice may not just be ineffectual. It could even be counter-productive, while many guidelines are arbitrary, based more on moral judgments than evidence.

Like all puritans, the public health evangelists delight in trumpeting the risks of regular alcohol consumption.

Yet last week alcohol expert Dr Kari Poikolainen, who used to work for the World Health Organisation, dismissed the official guidance that no one should drink more than the equivalent of glass of wine a day.

According to the extraordinary findings of Dr Poikolainen, who carried out long-term research into the effects of alcohol, drinking is dangerous only if you consume more than a bottle of wine or five pints of beer every day.

Those who drink more than the Government’s recommended daily limits still tend to be healthier than teetotallers.

The idea that it might not be risky to glug down an entire bottle of wine on a daily basis has sent a shudder through the public health lobby, since it makes a mockery of all their advice on drinking.

That is why they have reacted so defensively to Dr Poikolainen’s analysis.

“This is an unhelpful contribution,” said Julia Manning of think tank 2020Health. Yet the puritans’ pose of certainty is collapsing on other fronts.

In direct contradiction to their endless shrieking about obesity, a recent American study found that overweight pensioners live significantly longer than their lighter counterparts.

Other research has discovered that saturated fats, always presented as a deadly threat to our health, are actually good for us since they repair tissue, help the liver to function more effectively, preserve muscle and boost white blood cells in the fight against viruses.

This explains why some populations, such as the Masai people in Kenya, have diets full of saturated fats yet experience hardly any heart disease.

Similarly, some respected nutritionists argue that the “five-a-day” fad has no real scientific basis.

The slogan was actually devised as a marketing device in California in 1991, partly as a means of boosting the profits of agricultural producers.

Yet now it has taken on the form of sacred text. What the puritans ignore is human nature.

Rich food and alcoholic drink tend to make us happier and thereby improve our health by reducing our stress levels.

That is a truth encapsulated in the famous words of Winston Churchill: “I have taken more good from alcohol than alcohol has taken from me.”